_Caules Dulcamaræ_; _Bitter-sweet_, _Dulcamara_, _Woody Nightshade_; F.
_Douce-amère_, _Morelle grimpante_; G. _Bittersüss_.
=Botanical Origin=—_Solanum Dulcamara_ L., a perennial shrubby plant,
having small purple flowers and red berries, occurring throughout
Europe, except in the extreme north. It is also found in Northern
Africa, and in Asia Minor, and has become naturalized in North America.
It is common in moist, shady hedges and thickets.[1656]
=History=—Bitter nightshade, “manyglog,” was an ingredient, together
with wild sage and betony, of a drink which the Welsh “Physicians of
Myddfai” in the 13th century prepared for the bite of a mad dog.[1657]
The stalks of bitter-sweet were also used in the medical practice by
the German physicians and botanists of the 16th century, one of whom,
Tragus (1552), has figured and described it, under the name of _Dulcis
amara_ or _Dulcamarum_.
[1656] _Solanum nigrum_ L. which slightly resembles dulcamara, is a
low-growing annual or biennial, with _herbaceous_ stems, and berries
usually _black_.
[1657] _Meddygon Myddvai_ (see Appendix) 185. 293. 375.
=Description=—The older stems are woody; the upper and younger are
soft and green, long and straggling, attaining by the support of other
plants a height of 6 feet or more, and dying back in the winter. For
medicinal use, the shoots of a year or two old should be gathered,
either late in the year, or early in the spring before the leaves
come out. These shoots are several feet long, by about ⅕ of an inch
thick, of a light greenish-brown, sometimes cylindrical, at others
indistinctly 4-or 5-sided, slightly furrowed longitudinally, or
somewhat warty.
The thin, shining cork-bark easily exfoliates, showing beneath it the
mesophlœum which is rich in chlorophyll. The stalks are mostly hollow,
and partially filled with a whitish pith. The wood when dried is
about half or one-third as broad as the hollow centre, and the green
bark considerably narrower than the wood; the latter has a radiate
structure, and in older stems exhibits two or three sharply-defined
annual rings. The stems are usually cut into short lengths before being
dried for use.
The odour, which is rather fœtid and unpleasant, is to a great
extent dissipated by drying. The taste, at first slightly bitter, is
afterwards sweetish. The bitter appears to be more predominant in the
spring than in the autumn.
=Microscopic Structure=—The epidermis of younger shoots consists of
tabular thick-walled cells, many of them being elevated from the
surface as short blunt hairs. The older stems are covered with the
usual suberous envelope. The boundary between the mesophlœum and the
endophlœum is marked by a ring of strong liber-fibres, some of which
also occur in the pith. The woody part is rich in large vessels. In the
parenchymatous tissue of bitter-sweet, small crystals of oxalate of
calcium, not of a well-defined outline, and minute starch granules are
deposited.
=Chemical Composition=—The taste of bitter-sweet appears due,
according to Schoonbroodt (1867), to a bitter principle yielding by
decomposition, sugar and _Solanine_,—the latter in very small amount.
Solanine is an alkaloid; it was first prepared in 1820 by Desfosses, a
pharmacien at Besançon, from the berries of _Solanum nigrum_ L., and
was subsequently detected by the same chemist in the leaves and stalks
of _S. Dulcamara_, and by Peschier in the berries. Winckler (1841)
observed that the alkaloid of dulcamara stems can be obtained only
in an amorphous state, and that it behaves to platinic and mercuric
chlorides differently from the solanine of potatoes. Moitessier (1856)
confirmed this observation, and obtained only amorphous salts of the
solanine of bitter-sweet.
Zwenger and Kind on the one hand, and O. Gmelin on the other (1859
and 1858), found that solanine, C₄₃H₆₉NO₁₆ (or C₄₂H₈₇NO₁₅, according
to Hilger, 1879), is a conjugated compound of sugar and a peculiar
crystallizable alkaloid, _Solanidine_, C₂₆H₃₉NO (or C₂₆H₄₁NO₂?). The
latter, under the influence of strong hydrochloric acid, gives up
water, and is converted into the amorphous and likewise basic compound,
_Solanicine_.
Wittstein (1852) stated another alkaloid, dulcamarine, to be present
in the stems of bitter-sweet. But Geissler (1875) proved that this
substance, when perfectly pure, contains no nitrogen, and is not an
alkaloid. Geissler obtained his _Dulcamarin_ by warming an aqueous
decoction of the drug with charcoal, which he dried and exhausted with
boiling alcohol. This on evaporation afforded a yellowish amorphous
matter, which was dissolved in water and mixed with a very little
ammonia; a substance containing nitrogen then separated. The liquid was
evaporated, the residue again dissolved in alcohol, and the alcohol
distilled. Dulcamarin thus obtained is a yellowish powder of at first
bitter and subsequently permanently sweet taste. It dissolves in water
or alcohol, not in ether, chloroform, bisulphide of carbon. By boiling
dulcamarin with dilute acids it splits up according to the following
equation:—
C₂₂H₃₄O₁₀ + 2 OH₂ = C₆H₁₂O₆ · C₁₆H₂₆O₆.
Dulcamarin. Sugar. Dulcamaretin.
Dulcamaretin, a dark brown, tasteless mass, is soluble in alcohol, not
in water or ether.
=Uses=—Dulcamara is occasionally given in the form of decoction, in
rheumatic or cutaneous affections; but its real action, according to
Garrod, is unknown. This physician remarks[1658] that it does not
dilate the pupil or produce dryness of the throat like belladonna,
henbane or stramonium. He has given to a patient 3 pints of the
decoction _per diem_ without any marked action, and has also
administered as much as half a pound of the fresh berries with no ill
effect.
[1658] _Essentials of Materia Medica_, 1855. 196.